From what I can tell on the DPReview site, there's no way to change the shutter speed or aperture, directly or indirectly. Your camera will macro, you can get to within 2" away of your subject (that's pretty close).

FOr macro, check the specs for the camera. Specific models I know that will do a good job is the Canon G5 and Nikon Coolpix 4300. There are others too. Generally I think Nikon or Canon are good. Sony isn't well known for marco function.

digital rebel looks like a fantastic camera... especially for the price. invest in good lenses and you're set. the only reason i didn't go with the digital rebel was the lack of a few "studio oriented features" so i opted for 10D at twice the price.

For macros... get a set of Kenko Extension tubes (for your new rebel )... $150 will get you as much or as little macro as you like... (anyone feel the need to take a picture of the date on a dime?) and its a lot cheaper than buying a macro lens.